// SPDX-License-Identifier: GPL-2.0+

#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/regmap.h>
#include <linux/regulator/driver.h>

enum {
	RTQ6752_IDX_PAVDD = 0,
	RTQ6752_IDX_NAVDD = 1,
	RTQ6752_IDX_MAX
};

#define RTQ6752_REG_PAVDD	0x00
#define RTQ6752_REG_NAVDD	0x01
#define RTQ6752_REG_PAVDDONDLY	0x07
#define RTQ6752_REG_PAVDDSSTIME	0x08
#define RTQ6752_REG_NAVDDONDLY	0x0D
#define RTQ6752_REG_NAVDDSSTIME	0x0E
#define RTQ6752_REG_OPTION1	0x12
#define RTQ6752_REG_CHSWITCH	0x16
#define RTQ6752_REG_FAULT	0x1D

#define RTQ6752_VOUT_MASK	GENMASK(5, 0)
#define RTQ6752_NAVDDEN_MASK	BIT(3)
#define RTQ6752_PAVDDEN_MASK	BIT(0)
#define RTQ6752_PAVDDAD_MASK	BIT(4)
#define RTQ6752_NAVDDAD_MASK	BIT(3)
#define RTQ6752_PAVDDF_MASK	BIT(3)
#define RTQ6752_NAVDDF_MASK	BIT(0)
#define RTQ6752_ENABLE_MASK	(BIT(RTQ6752_IDX_MAX) - 1)

#define RTQ6752_VOUT_MINUV	5000000
#define RTQ6752_VOUT_STEPUV	50000
#define RTQ6752_VOUT_NUM	47
#define RTQ6752_I2CRDY_TIMEUS	1000
#define RTQ6752_MINSS_TIMEUS	5000

struct rtq6752_priv {
	struct regmap *regmap;
	struct gpio_desc *enable_gpio;
	struct mutex lock;
	unsigned char enable_flag;
};

static int rtq6752_set_vdd_enable(struct regulator_dev *rdev)
{
	struct rtq6752_priv *priv = rdev_get_drvdata(rdev);
	int rid = rdev_get_id(rdev), ret;

	mutex_lock(&priv->lock);
	if (!priv->enable_flag && priv->enable_gpio) {
		gpiod_set_value(priv->enable_gpio, 1);

		usleep_range(RTQ6752_I2CRDY_TIMEUS,
			     RTQ6752_I2CRDY_TIMEUS + 100);

		regcache_cache_only(priv->regmap, false);
		ret = regcache_sync(priv->regmap);
		if (ret) {
			mutex_unlock(&priv->lock);
			return ret;
		}
	}

	priv->enable_flag |= BIT(rid);
	mutex_unlock(&priv->lock);

	return regulator_enable_regmap(rdev);
}

static int rtq6752_set_vdd_disable(struct regulator_dev *rdev)
{
	struct rtq6752_priv *priv = rdev_get_drvdata(rdev);
	int rid = rdev_get_id(rdev), ret;

	ret = regulator_disable_regmap(rdev);
	if (ret)
		return ret;

	mutex_lock(&priv->lock);
	priv->enable_flag &= ~BIT(rid);

	if (!priv->enable_flag && priv->enable_gpio) {
		regcache_cache_only(priv->regmap, true);
		regcache_mark_dirty(priv->regmap);

		gpiod_set_value(priv->enable_gpio, 0);
	}
	mutex_unlock(&priv->lock);

	return 0;
}

static int rtq6752_get_error_flags(struct regulator_dev *rdev,
				   unsigned int *flags)
{
	unsigned int val, events = 0;
	const unsigned int fault_mask[] = {
		RTQ6752_PAVDDF_MASK, RTQ6752_NAVDDF_MASK };
	int rid = rdev_get_id(rdev), ret;

	ret = regmap_read(rdev->regmap, RTQ6752_REG_FAULT, &val);
	if (ret)
		return ret;

	if (val & fault_mask[rid])
		events = REGULATOR_ERROR_REGULATION_OUT;

	*flags = events;
	return 0;
}

static const struct regulator_ops rtq6752_regulator_ops = {
	.list_voltage = regulator_list_voltage_linear,
	.set_voltage_sel = regulator_set_voltage_sel_regmap,
	.get_voltage_sel = regulator_get_voltage_sel_regmap,
	.enable = rtq6752_set_vdd_enable,
	.disable = rtq6752_set_vdd_disable,
	.is_enabled = regulator_is_enabled_regmap,
	.set_active_discharge = regulator_set_active_discharge_regmap,
	.get_error_flags = rtq6752_get_error_flags,
};

static const struct regulator_desc rtq6752_regulator_descs[] = {
	{
		.name = "rtq6752-pavdd",
		.of_match = of_match_ptr("pavdd"),
		.regulators_node = of_match_ptr("regulators"),
		.id = RTQ6752_IDX_PAVDD,
		.n_voltages = RTQ6752_VOUT_NUM,
		.ops = &rtq6752_regulator_ops,
		.owner = THIS_MODULE,
		.min_uV = RTQ6752_VOUT_MINUV,
		.uV_step = RTQ6752_VOUT_STEPUV,
		.enable_time = RTQ6752_MINSS_TIMEUS,
		.vsel_reg = RTQ6752_REG_PAVDD,
		.vsel_mask = RTQ6752_VOUT_MASK,
		.enable_reg = RTQ6752_REG_CHSWITCH,
		.enable_mask = RTQ6752_PAVDDEN_MASK,
		.active_discharge_reg = RTQ6752_REG_OPTION1,
		.active_discharge_mask = RTQ6752_PAVDDAD_MASK,
		.active_discharge_off = RTQ6752_PAVDDAD_MASK,
	},
	{
		.name = "rtq6752-navdd",
		.of_match = of_match_ptr("navdd"),
		.regulators_node = of_match_ptr("regulators"),
		.id = RTQ6752_IDX_NAVDD,
		.n_voltages = RTQ6752_VOUT_NUM,
		.ops = &rtq6752_regulator_ops,
		.owner = THIS_MODULE,
		.min_uV = RTQ6752_VOUT_MINUV,
		.uV_step = RTQ6752_VOUT_STEPUV,
		.enable_time = RTQ6752_MINSS_TIMEUS,
		.vsel_reg = RTQ6752_REG_NAVDD,
		.vsel_mask = RTQ6752_VOUT_MASK,
		.enable_reg = RTQ6752_REG_CHSWITCH,
		.enable_mask = RTQ6752_NAVDDEN_MASK,
		.active_discharge_reg = RTQ6752_REG_OPTION1,
		.active_discharge_mask = RTQ6752_NAVDDAD_MASK,
		.active_discharge_off = RTQ6752_NAVDDAD_MASK,
	}
};

static int rtq6752_init_device_properties(struct rtq6752_priv *priv)
{
	u8 raw_vals[] = { 0, 0 };
	int ret;

	/* Configure PAVDD on and softstart delay time to the minimum */
	ret = regmap_raw_write(priv->regmap, RTQ6752_REG_PAVDDONDLY, raw_vals,
			       ARRAY_SIZE(raw_vals));
	if (ret)
		return ret;

	/* Configure NAVDD on and softstart delay time to the minimum */
	return regmap_raw_write(priv->regmap, RTQ6752_REG_NAVDDONDLY, raw_vals,
				ARRAY_SIZE(raw_vals));
}

static bool rtq6752_is_volatile_reg(struct device *dev, unsigned int reg)
{
	if (reg == RTQ6752_REG_FAULT)
		return true;
	return false;
}

static const struct reg_default rtq6752_reg_defaults[] = {
	{ RTQ6752_REG_PAVDD, 0x14 },
	{ RTQ6752_REG_NAVDD, 0x14 },
	{ RTQ6752_REG_PAVDDONDLY, 0x01 },
	{ RTQ6752_REG_PAVDDSSTIME, 0x01 },
	{ RTQ6752_REG_NAVDDONDLY, 0x01 },
	{ RTQ6752_REG_NAVDDSSTIME, 0x01 },
	{ RTQ6752_REG_OPTION1, 0x07 },
	{ RTQ6752_REG_CHSWITCH, 0x29 },
};

static const struct regmap_config rtq6752_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.cache_type = REGCACHE_RBTREE,
	.max_register = RTQ6752_REG_FAULT,
	.reg_defaults = rtq6752_reg_defaults,
	.num_reg_defaults = ARRAY_SIZE(rtq6752_reg_defaults),
	.volatile_reg = rtq6752_is_volatile_reg,
};

static int rtq6752_probe(struct i2c_client *i2c)
{
	struct rtq6752_priv *priv;
	struct regulator_config reg_cfg = {};
	struct regulator_dev *rdev;
	int i, ret;

	priv = devm_kzalloc(&i2c->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	mutex_init(&priv->lock);

	priv->enable_gpio = devm_gpiod_get_optional(&i2c->dev, "enable",
						    GPIOD_OUT_HIGH);
	if (IS_ERR(priv->enable_gpio)) {
		dev_err(&i2c->dev, "Failed to get 'enable' gpio\n");
		return PTR_ERR(priv->enable_gpio);
	}

	usleep_range(RTQ6752_I2CRDY_TIMEUS, RTQ6752_I2CRDY_TIMEUS + 100);
	/* Default EN pin to high, PAVDD and NAVDD will be on */
	priv->enable_flag = RTQ6752_ENABLE_MASK;

	priv->regmap = devm_regmap_init_i2c(i2c, &rtq6752_regmap_config);
	if (IS_ERR(priv->regmap)) {
		dev_err(&i2c->dev, "Failed to init regmap\n");
		return PTR_ERR(priv->regmap);
	}

	ret = rtq6752_init_device_properties(priv);
	if (ret) {
		dev_err(&i2c->dev, "Failed to init device properties\n");
		return ret;
	}

	reg_cfg.dev = &i2c->dev;
	reg_cfg.regmap = priv->regmap;
	reg_cfg.driver_data = priv;

	for (i = 0; i < ARRAY_SIZE(rtq6752_regulator_descs); i++) {
		rdev = devm_regulator_register(&i2c->dev,
					       rtq6752_regulator_descs + i,
					       &reg_cfg);
		if (IS_ERR(rdev)) {
			dev_err(&i2c->dev, "Failed to init %d regulator\n", i);
			return PTR_ERR(rdev);
		}
	}

	return 0;
}

static const struct of_device_id __maybe_unused rtq6752_device_table[] = {
	{ .compatible = "richtek,rtq6752", },
	{}
};
MODULE_DEVICE_TABLE(of, rtq6752_device_table);

static struct i2c_driver rtq6752_driver = {
	.driver = {
		.name = "rtq6752",
		.of_match_table = rtq6752_device_table,
	},
	.probe_new = rtq6752_probe,
};
module_i2c_driver(rtq6752_driver);

MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
MODULE_DESCRIPTION("Richtek RTQ6752 Regulator Driver");
MODULE_LICENSE("GPL v2");